Most of the medical X-ray images for diagnosis are created through absorption contrast imaging. In the absorption contrast imaging, the contrast is defined by differences in attenuation of the intensity of X rays that passed a subject. In contrast, in phase contrast imaging, the contrast is defined by phase shifts in X rays instead of absorption of the X rays.
For example, Patent Literature 1 discloses an X-ray imaging system to create an X-ray image with a high level of visibility through the edge enhancement utilizing the refraction of X rays in a magnified imaging operation. Patent Literature 1 also discloses the superimposition of a phase contrast image on an absorption contrast image.
Patent Literature 2 discloses the creation of a phase contrast image through tomography and the superimposition of the phase contrast image obtained by tomography on an absorption image created through tomography in the field of computerized tomography (CT).